U.S. patent application number 14/199100 was filed with the patent office on 2014-09-11 for polycarboxylate ethers with branched side chains.
The applicant listed for this patent is Construction Research & Technology GmbH. Invention is credited to Rabie AL-HELLANI, Anna CRISTADORO, Joachim DENGLER, Silke FLAKUS, Alexander KRAUS, Ida ROS, Nicoletta ZEMINIAN.
Application Number | 20140256857 14/199100 |
Document ID | / |
Family ID | 51488575 |
Filed Date | 2014-09-11 |
United States Patent
Application |
20140256857 |
Kind Code |
A1 |
DENGLER; Joachim ; et
al. |
September 11, 2014 |
POLYCARBOXYLATE ETHERS WITH BRANCHED SIDE CHAINS
Abstract
A method of utilizing a copolymer for dispersing inorganic
binders, the copolymer comprising as comonomers in copolymerized
form at least one ethylenically unsaturated acid monomer and at
least one ethylenically unsaturated, branched polyether
macromonomer. Further disclosed are dispersants for inorganic
binders, comprising the subject copolymer, and building material
mixtures comprising inorganic binders and the subject
dispersant.
Inventors: |
DENGLER; Joachim;
(Tacherting Wajon, DE) ; KRAUS; Alexander;
(Pittenhart, DE) ; AL-HELLANI; Rabie;
(Ludwigshafen, DE) ; CRISTADORO; Anna; (Raleigh,
NC) ; FLAKUS; Silke; (Ebersberg, DE) ;
ZEMINIAN; Nicoletta; (Treviso, IT) ; ROS; Ida;
(Zero Branco TV, IT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Construction Research & Technology GmbH |
Trostberg |
|
DE |
|
|
Family ID: |
51488575 |
Appl. No.: |
14/199100 |
Filed: |
March 6, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61773211 |
Mar 6, 2013 |
|
|
|
Current U.S.
Class: |
524/5 ;
526/318.5 |
Current CPC
Class: |
C08F 290/142 20130101;
C04B 24/165 20130101; C08F 220/06 20130101; C08F 220/06 20130101;
C04B 24/2605 20130101; C04B 24/2647 20130101; C08F 283/065
20130101; C08F 283/065 20130101; C04B 24/2641 20130101; C04B
24/2664 20130101; C04B 2103/408 20130101; C08F 290/142 20130101;
C04B 24/246 20130101 |
Class at
Publication: |
524/5 ;
526/318.5 |
International
Class: |
C04B 24/26 20060101
C04B024/26 |
Claims
1. A method of utilizing a copolymer for dispersing inorganic
binders, the copolymer comprising as comonomers in copolymerized
form: (A) at least one ethylenically unsaturated acid monomer, (B)
at least one ethylenically unsaturated, branched polyether
macromonomer of the general formula E-V.sub.kL.sub.k+1, where E is
an ethylenically unsaturated structural unit which comprises at
least one ether, carboxylic ester or carboxamide structural unit, V
is a branched structural unit of the formula
--CH(CH.sub.2O--).sub.2, and L is a linear structural unit of the
formula -[A.sup.1O].sub.l-A.sup.2, where A.sup.1 in each case
independently is selected from C.sub.2-C.sub.10 alkylene,
C.sub.6-C.sub.10 arylene and/or C.sub.7-C.sub.10 aralkylene,
A.sup.2 in each case independently is selected from
C.sub.1-C.sub.30 alkyl, C.sub.3-C.sub.10 cycloalkyl,
C.sub.6-C.sub.30 aryl and/or C.sub.7-C.sub.30 aralkyl, k is an
integer from 1 to 7, and l in each case independently is an integer
from 1 to 350.
2. The method according to claim 1, characterized in that the
inorganic binder is selected from cements, portland cements,
aluminate cements, .alpha.-calcium sulphate hemihydrate,
.beta.-calcium sulphate hemihydrate, anhydrite, lime, industrial
slags synthetic slags, blast furnace slags, slag sand, ground slag
sand, electrothermal phosphorus slag, stainless steel slag,
pozzolanic binders, fly ashes, brown coal fly ash, mineral coal fly
ash, microsilica, metakaolin, natural pozzolans, tuff, trass,
volcanic ash, natural zeolites, synthetic zeolites, calcined oil
shale and mixtures of these.
3. The method according to claim 1, characterized in that the at
least one copolymerized ethylenically unsaturated acid monomer (A)
is present in the copolymer in the form of one of the following
structural units (Ia) to (Id): ##STR00009## where R.sup.1 in each
case independently is selected from H, an unbranched and/or
branched C.sub.1-C.sub.4 alkyl group, X in each case independently
is selected from a single bond, --NH--(C.sub.mH.sub.2m)-- and/or
--O--(C.sub.mH.sub.2m)--, where m is an integer from 1 to 4,
R.sup.2 in each case independently is selected from --OM.sub.1/q,
--SO.sub.3M.sub.1/q, --PO.sub.3M.sub.2/q, --O--PO.sub.3M.sub.2/q,
--C.sub.6H.sub.4--SO.sub.3M.sub.1/q,
--C.sub.6H.sub.4--PO.sub.3M.sub.2/q and/or
--C.sub.6H.sub.4--OPO.sub.3M.sub.2/q, where M is selected from H,
alkali metals, alkaline earth metals, aluminium and/or metals of
the first transition series, and q represents the charge number of
M, with the proviso that R.sup.2 is represented by --OM.sub.1/q if
X is a single bond; ##STR00010## where R.sup.3 has the meaning
given above for R.sup.1, n is an integer from 0 to 4, R.sup.4 in
each case independently is selected from --SO.sub.3M.sub.1/q,
--PO.sub.3M.sub.2/q, --O--PO.sub.3M.sub.2/q and/or
--C.sub.6H.sub.4--SO.sub.3M.sub.1/q, where M and q have the
meanings stated above; ##STR00011## where R.sup.5 has the meaning
given above for R.sup.1, Z in each case independently is selected
from --O-- and/or --NH--; ##STR00012## where R.sup.6 has the
meaning given above for R.sup.1, Q has the meaning given above for
X and, R.sup.7 has the meaning given above for R.sup.2.
4. The method according to claim 3, characterized in that in the
formula (Ia) R.sup.1 is H or methyl, X in each case independently
is selected from --NH--(C.sub.mH.sub.2m)--,
--O--(C.sub.mH.sub.2m)--, --O--(C.sub.2H.sub.4)--, and
--NH--(C(CH.sub.3).sub.2CH.sub.2)--, and R.sup.2 is
--O--PO.sub.3M.sub.2/q, or --O--SO.sub.3M.sub.1/q, where m, M and q
have the meanings given above.
5. The method according to claim 1, characterized in that the acid
monomer (A) or the acid monomers (A) is or are selected from
(meth)acrylic acid and salts thereof, maleic acid, its monoesters,
monoamides and salts, maleic anhydride and/or hydroxyalkyl
(meth)acrylic phosphoric esters and salts thereof.
6. The method according to claim 1, characterized in that the
copolymer comprises as additional comonomer in copolymerized form
an unbranched polyether macromonomer of the general formula E-L
where E and L have the meanings given above.
7. The method according to claim 1, characterized in that the
structural unit E in each case independently is selected from a
vinyl ether, allyl ether, isopreneyl ether, (meth)acrylic ester,
(meth)acrylamide, maleic monoester and/or maleic monoamide
unit.
8. The method according to claim 1, characterized in that the
ethylenically unsaturated structural unit E is present in the form
of E*-S, where E* in each case independently is selected from a
vinyl ether, allyl ether, (meth)acrylic ester and/or maleic
monoester unit and S is a (poly)alkylene glycol unit
-[A.sup.3O].sub.m--, where A.sup.3 in each case independently is
selected from C.sub.2-C.sub.10 alkylene, C.sub.6-C.sub.10 arylene
and/or C.sub.7-C.sub.10 aralkylene, and m is in each case
independently an integer from 1 to 50.
9. The method according to claim 1, characterized in that A.sup.1
in each case independently is present to an extent of more than 60
mol %, based on all of the structural units of the formula
-[A.sup.1O].sub.l, in the form of --C.sub.2H.sub.4--, A.sup.2 in
each case independently is selected from C.sub.1-C.sub.4 alkyl, k
is an integer from 1 to 3 and l in each case independently is an
integer from 2 to 100.
10. The method according to claim 1, characterized in that the
branched polyether macromonomer (B) has a molecular weight in the
range from 700 to 15 000 g/mol.
11. The method according to claim 1, characterized in that the
molar ratio of (A) acid monomer to (B) polyether macromonomer is
from 20/1 to 1/1.
12. The method according to claim 1, characterized in that the
copolymer is obtained by radical polymerization in the presence of
the ethylenically unsaturated acid monomer (A) and of the
ethylenically unsaturated polyether macromonomer (B), so that in
total at least 45 mol % of all of the structural units of the
copolymer have been produced by copolymerization of acid monomer
(A) and polyether macromonomer (B).
13. Dispersant for inorganic binders, comprising a copolymer as
defined in claim 1.
14. Building material mixture comprising inorganic binders and a
dispersant according to claim 13.
15. The building material according to claim 14, wherein the
inorganic binder is cement.
Description
[0001] The present application claims the benefit of the filing
date of U.S. Provisional Application for Patent, U.S. Ser. No.
61/773,211, filed Mar. 6, 2013, under 35 U.S.C. .sctn.119(e), which
application is incorporated by reference herein.
[0002] Provided is a method for utilizing a copolymer for
dispersing inorganic binders, the copolymer comprising as
comonomers in copolymerized form: [0003] (A) at least one
ethylenically unsaturated acid monomer, [0004] (B) at least one
ethylenically unsaturated, branched polyether macromonomer of the
general formula E-V.sub.kL.sub.k+1, where [0005] E is an
ethylenically unsaturated structural unit which comprises at least
one ether, carboxylic ester or carboxamide structural unit, [0006]
V is a branched structural unit of the formula
--CH(CH.sub.2O--).sub.2, and [0007] L is a linear structural unit
of the formula -[A.sup.1O].sub.l-A.sup.2, where [0008] A.sup.1 in
each case independently is selected from C.sub.2-C.sub.10 alkylene,
C.sub.6-C.sub.10 arylene and/or C.sub.7-C.sub.10 aralkylene,
preferably --C.sub.2H.sub.4--, [0009] A.sup.2 in each case
independently is selected from C.sub.1-C.sub.30 alkyl,
C.sub.3-C.sub.10 cycloalkyl, C.sub.6-C.sub.30 aryl and/or
C.sub.7-C.sub.30 aralkyl, preferably C.sub.1-C.sub.4 alkyl, [0010]
k is an integer from 1 to 7, preferably from 1 to 3, and [0011] l
in each case independently is an integer from 1 to 350, preferably
from 2 to 100, more particularly from 5 to 70 and very preferably
from 7 to 17.
[0012] It is known that aqueous slurries of organic or inorganic
substances in powder form, such as clays, ground silicate, chalk,
carbon black, ground rock and hydraulic binders are often admixed
with admixtures in the form of dispersants for the purpose of
improving their processing properties, i.e. kneadability,
spreadability, sprayability, pumpability or fluidity. Such
admixtures are capable of disrupting agglomerated solids,
dispersing the particles formed, and in this way improving the
fluidity. This effect is also exploited in particular, in a
targeted way, in the production of building material mixtures which
comprise hydraulic binders, such as cement, lime, gypsum, calcium
sulphate hemihydrate (bassanite) or anhydrous calcium sulphate
(anhydrite), or latent hydraulic binders such as fly ash, blast
furnace slag or pozzolans.
[0013] To convert these building material mixtures, based on the
stated binders, into a ready-to-use processable form, there is
generally a need for a substantially greater amount of batching
water than would be necessary for the subsequent hydration and
hardening process. The cavity fraction in the concrete element,
formed by the excess water that later evaporates, leads to
significantly impaired mechanical strengths and resistance
properties.
[0014] To reduce this excess water fraction for a given processing
consistency, and/or to improve the processing properties for a
given water/binder ratio, admixtures are used that are generally
identified as water reducers or superplasticizers. Employed more
particularly as such admixtures in practice are copolymers prepared
by radical copolymerization of acid monomers with polyether
macromonomers. Concrete plasticizers are added to the concrete
alongside other additives in order either to facilitate processing
at a constant water/cement value or to obtain plastic viscosity in
the case of reduced water/cement values. By this means it is
possible, for example, to improve the concrete's pumpability or to
raise the compressive strength and density and to shorten the cure
time. Currently in use as concrete plasticizers are
lignosulphonates, sulphonated melamine-formaldehyde resins and
naphthalene-formaldehyde resins, and also polycarboxylates.
Examples of polycarboxylates are, for example, copolymers of maleic
acid and/or acrylic acid with polyether macromonomers (e.g.
alkoxylated vinyl ethers or (meth)acrylate esters of
alkylpolyalkylene glycols).
[0015] Dispersants based on polycarboxylate ethers (PCEs) can be
adapted individually to the requirements of the concrete industry.
This is done by modifying the chemical composition of the
copolymers. PCEs generally have a main polymer chain of carbon
atoms and side chains which comprise polyether structures. Located
on the main polymer chain are acid groups. It is possible to modify
the side chain length and the molar ratios of the acid groups and
polyether side chains in order to obtain concrete of a very high
quality.
[0016] For concrete for precast component works, superplasticizers
are required that allow a very high plasticizing effect, rapid
setting, good early strength, and low viscosity in the cement
produced using them. High plasticizing effect combined with good
early strengths are presently available, however, only from
superplasticizers having relatively long (greater than 3000 g/mol)
polyether side chains, as described for example in WO/05075529 A2.
Usually, however, this causes the fresh concrete to have a
decidedly high viscosity. As a result of this, the fresh concrete,
especially in the case of low W/C values, is very difficult to
place and is difficult to shape. Consequently, in the precast
component works, the moulds can only be reliably filled at high
cost and complexity.
[0017] Pumpable concrete and ready-mixed concrete require a
relatively wide time window within which the concrete possesses the
same consistency and processing properties. Here, the mixing times
tend to play a minor part, while the slump retention (retention of
consistency) is very important here. Since the pump pressure
correlates with the viscosity (Buckingham-Reiner equation), and in
order to minimize the mechanical abrasion and cost and complexity
of instrumentation, the viscosity ought to be extremely low for a
long time even in the case of pumpable concrete. As mentioned above
for the precast component concrete, high viscosities in the fresh
concrete are very deleterious to processing properties.
[0018] For the stated applications, however, there are presently no
acceptable solutions that combine sufficient dispersability with,
in particular, low concrete viscosities.
[0019] A concrete admixture that supplies relatively low viscosity
on the part of the concrete is OPTIMA.RTM. 100 from Chryso, for
example. This dispersant, which is based not on a polycarboxylate
technology (phosphonated polyether, corresponding to WO 2010/112775
A1), is restricted in its use, however, since particularly at low
W/C values it often does not display adequate plasticizing. The
said product also often has retarding properties and is generally
not so suitable for concrete for precast components.
[0020] The market presently requires dispersants which allow a high
dispersing effect, a low concrete viscosity, and the effective
development of early strength in the concrete.
[0021] Disclosed in (US2011/0015361 A1) are copolymers which have
in copolymerized form at least one ethylenically unsaturated
monocarboxylic or dicarboxylic acid and at least one structural
unit of the general formula I. The general formula I exhibits
partial overlap with the branched polyether macromonomers (B)
disclosed herein. However, US2011/0015361 A1 gives no indication at
all of the use as water reducers in inorganic binders or concrete,
instead disclosing applications as thickeners in the sectors of
laundry detergents and cleaners (textile segment) and also in the
cosmetic sector.
[0022] The present patent application provides dispersants for
dispersing inorganic binders, more particularly dispersants for use
in cementitious systems such as concrete and mortar, which allow a
sufficient dispersing effect, and more particularly, a low
viscosity on the part of the concrete of the concrete.
[0023] This is achieved through utilizing, such as by admixing, a
copolymer for dispersing inorganic binders, the copolymer
comprising as comonomers in copolymerized form: [0024] (A) at least
one ethylenically unsaturated acid monomer, [0025] (B) at least one
ethylenically unsaturated, branched polyether macromonomer of the
general formula E-V.sub.kL.sub.k+1, the parameters E, V, .sub.k,
and L being defined as specified above.
[0026] The inorganic binder may be selected from cements, from
cements, more particularly portland cements and aluminate cements,
from .alpha.-calcium sulphate hemihydrate, .beta.-calcium sulphate
hemihydrate, anhydrite and lime, from industrial and synthetic
slags, more particularly blast furnace slags, slag sand, ground
slag sand, electrothermal phosphorus slag and stainless steel slag,
from pozzolanic binders, more particularly fly ashes, preferably
brown coal fly ash and mineral coal fly ash, microsilica,
metakaolin, natural pozzolans, more particularly tuff, trass and
volcanic ash, natural and synthetic zeolites, calcined oil shale
and mixtures of these. A preferred binder is (portland) cement. The
subject superplasticizers may be metered preferably at from 0.1 to
1 wt %, based on the inorganic binder or binders, preferably 0.2 to
0.6 wt %.
Subject Copolymers (Dispersants)
[0027] As far as the dispersing mechanisms of the polycarboxylate
ethers is concerned, the conceptualization assumes that the
anionically charged acid groups of the polycarboxylate ethers
attached to the surfaces of the cement grain, that as a result of
calcium ions have a positive charge. The hydrophilic polyether side
chains point predominantly away from the cement grain, into the
likewise hydrophilic aqueous pore solution of the cementitious
binder batched with water.
[0028] In contrast to linear polyether side chains of the prior
art, the present dispersants comprise at least singly or else
multiply branched polyether side chains. For the same mass, the
subject polyether macromonomers (B) are certainly greater in their
steric bulk. More particularly they differ in their length (for the
same mass), with the subject polyether macromonomers (B) being
shorter on account of the branching. Surprisingly it has been found
that these structural differences lead to a reduction in the
viscosity of fresh concrete. This has the advantage that a
relatively high plasticizing effect and in particular a low
viscosity (better processing/pumping properties) can be
obtained.
[0029] In the case of conventional PCEs with unbranched, more
particularly long, polyether side chains, the inventors, in the
course of their work, arrived at the hypothesis that an interaction
("hooking") of the long linear polyether side chains into one
another could be seen as a reason for the high viscosity of the
resultant concrete. As a result of this interaction there are also
interactions between polyether side chains attached on different
cement grains, thus explaining the higher viscosity of the
concrete. The inorganic binder particles, preferably cement
particles, are less well dispersed. As the length of the side chain
goes up, this effect increases, and the interactions (presumably
mediated via the PCEs) between the dispersed cement grain particles
become stronger, a phenomenon manifested macrophysically in an
increase in the viscosity of the concrete.
[0030] In the text below, the present dispersants, constructed from
acid monomers (A) and polyether macromonomers (B), will be
described in more detail.
Acid Monomer (A)
[0031] Possible examples of (A) ethylenically unsaturated acid
monomer include carboxylic acid monomers, especially monocarboxylic
or dicarboxylic acid monomers, sulphonic acid monomers, phosphonic
acid monomers and/or phosphoric ester monomers. Among the
phosphoric ester monomers, the phosphoric monoester monomers are
preferred, and it is also possible to utilize phosphoric diester
monomers. Preferred are carboxylic acid monomers and phosphoric
ester monomers; sulphonic acid monomers are less preferred. The
stated acid monomers may be used both in their (partially)
neutralized form (by alkalis such as alkali metal- or alkaline
earth metal-based alkalis, ammonia, organic amines, etc., for
example), and in their acidic form. Independently of one another it
is possible for one or more kinds of ethylenically unsaturated acid
monomers to be employed. The acid monomer (A) is preferably
monoethylenically unsaturated.
[0032] Examples of suitable monoethylenically unsaturated
dicarboxylic acids are itaconic acid, citraconic acid, mesaconic
acid, glutaconic acid, aconitic acid, maleic acid, fumaric acid,
maleic anhydride, itaconic anhydride and mixtures of two or more of
the aforementioned compounds, including the respective salts.
Particularly preferred is maleic acid, which can also be used in
the anhydride form.
[0033] Suitable monoethylenically unsaturated monomer carboxylic
acids are (meth)acrylic acid, ethacrylic acid, and (E)- and
(Z)-crotonic acid. Preferred is (meth)acrylic acid; acrylic acid is
especially preferred.
[0034] Also preferred is utilizing one or more monoethylenically
unsaturated monocarboxylic acids and one or more monoethylenically
unsaturated dicarboxylic acids; utilizing maleic acid and acrylic
acid is especially preferred.
[0035] Preference is given to the method of utilizing characterized
in that the at least one copolymerized ethylenically unsaturated
acid monomer (A) is present in the copolymer in the form of one of
the following structural units (Ia) to (Id):
##STR00001## [0036] where [0037] R.sup.1 in each case independently
is selected from H, an unbranched and/or branched C.sub.1-C.sub.4
alkyl group, [0038] X in each case independently is selected from a
single bond, --NH--(C.sub.mH.sub.2m)-- and/or
--O--(C.sub.mH.sub.2O--, where m is an integer from 1 to 4, [0039]
R.sup.2 in each case independently is selected from --OM.sub.1/q,
--SO.sub.3M.sub.1/3, --PO.sub.3M.sub.2/q, --O--PO.sub.3M.sub.2/q,
--C.sub.6H.sub.4--SO.sub.3M.sub.1/q,
--C.sub.6H.sub.4--PO.sub.3M.sub.2/q and/or
--C.sub.6H.sub.4--OPO.sub.3M.sub.2/q, where M is selected from H,
alkali metals, alkaline earth metals, aluminium and/or metals of
the first transition series, and q represents the charge number of
M, with the proviso that R.sup.2 is represented by --OM.sub.1/q if
X is a single bond;
[0039] ##STR00002## [0040] where [0041] R.sup.3 has the meaning
given above for R.sup.1, [0042] n is an integer from 0 to 4, [0043]
R.sup.4 in each case independently is selected from
--SO.sub.3M.sub.1/q, --PO.sub.3M.sub.2/q, --O--PO.sub.3M.sub.2/q
and/or --C.sub.6H.sub.4--SO.sub.3M.sub.1/q, where M and q have the
meanings stated above;
[0043] ##STR00003## [0044] where [0045] R.sup.5 has the meaning
given above for R.sup.1, [0046] Z in each case independently is
selected from --O-- and/or --NH--;
[0046] ##STR00004## [0047] where [0048] R.sup.6 has the meaning
given above for R.sup.1, [0049] Q has the meaning given above for X
and, [0050] R.sup.7 has the meaning given above for R.sup.2.
[0051] Preference is given to the method of utilizing characterized
in that in the formula (Ia) [0052] R.sup.1 is H or methyl, [0053] X
in each case independently is selected from
--NH--(C.sub.mH.sub.2m)-- and --O--(C.sub.mH.sub.2m)-- and
preferably is --O--(C.sub.2H.sub.4)-- or
--NH--(C(CH.sub.3).sub.2CH.sub.2)--, and [0054] R.sup.2 is
--O--PO.sub.3M.sub.2/q or --O--SO.sub.3M.sub.1/q, where m, M and q
have the meanings given above.
[0055] Preference as radical R.sup.2 in the formula (Ia) is
additionally given to --O--PO.sub.3M.sub.2/q, and as X
--O--(C.sub.mH.sub.2m). Particularly preferred as
phosphorous-containing acid monomers (A) are hydroxyethyl
(meth)acrylic phosphoric ester (HE(M)A-phosphate) and hydroxypropyl
(meth)acrylic phosphoric ester (HP(M)A-phosphate) and in each case
their salts. The corresponding diphosphoric esters may likewise be
used, but are less preferred.
[0056] Preference is given to the method of utilizing characterized
in that the acid monomer (A) or the acid monomers (A) is or are
selected from (meth)acrylic acid and salts thereof, maleic acid,
its monoesters, monoamides and salts, maleic anhydride and/or
hydroxyalkyl (meth)acrylic phosphoric esters and salts thereof,
with preference being given to hydroxyethyl (meth)acrylic
phosphoric ester and hydroxypropyl (meth)acrylic phosphoric ester
and in each case their salts.
Polyether Macronomomer (B)
[0057] The subject copolymers comprise as comonomer in
copolymerized form at least one ethylenically unsaturated, branched
polyether macromonomer (B) of the general formula (I)
E-V.sub.kL.sub.k+1. In the copolymer it is possible to employ
independently of one another identical or different polyether
macromonomers (B).
[0058] (B) in the general formula (I) comprises an ethylenically
unsaturated, preferably a monoethylenically unsaturated, structural
unit (E), which comprises at least one ether, carboxylic ester or
carboxamide structural unit. The ether and carboxylic ester
structural units preferably comprise exclusively oxygen atoms, in
contrast to, for example, sulphur-containing embodiments such as
sulphur ethers. The structural unit E preferably comprises two to
six carbon atoms and at least one oxygen atom, more preferably two
to five carbon atoms and at least one oxygen atom.
[0059] Examples of E which comprise ethers are
CH.sub.2.dbd.CH--O--, CH.sub.2.dbd.CH--O--(CH.sub.2).sub.4--O--,
CH(CH.sub.3).dbd.CH--O--, CH.sub.2.dbd.CH--O--[A.sup.3O].sub.m--,
where -A.sup.3 in each case independently is selected from
C.sub.2-C.sub.10 alkylene, C.sub.6-C.sub.10 arylene and/or
C.sub.7-C.sub.10 aralkylene; preferably A.sup.3 is
--C.sub.2H.sub.4--; m is in each case independently an integer from
1 to 50, preferably from 2 to 40, especially preferably from 5 to
25. It is particularly preferred for A.sup.3 in each case
independently of one another to be present at more than 60 mol %,
based on all of the structural units of the formula
-[A.sup.3O].sub.m in the form of --C.sub.2H.sub.4--. The
aforementioned ethers are vinyl ethers, since an oxygen atom is
located directly on the unsaturated structural unit. Vinyl ethers
are preferred since they are relatively reactive and easy to
prepare.
[0060] Further examples E which comprise ethers include the
(meth)allyl ethers (CH.sub.2.dbd.CH--CH.sub.2--O--, or
CH.sub.2.dbd.C(Me)--CH.sub.2--O--), and the isoprenol ethers
(CH.sub.2.dbd.CMe-(CH.sub.2).sub.2--O--).
[0061] Among the ethylenically unsaturated carboxylic esters there
is a preferred distinction between monocarboxylic acid derivatives
and dicarboxylic acid derivatives.
[0062] Examples of monoethylenic unsaturated structural units E
from the area of the monocarboxylic acid derivatives are
(meth)acrylic esters such as CH.sub.2.dbd.CH--COO--,
CH.sub.2.dbd.CMe-COO--, CH.sub.2.dbd.CH--COO--[A.sup.3O].sub.m--,
CH.sub.2.dbd.CMe-COO--[A.sup.3O].sub.m--, and the corresponding
esters of (E)- and (Z)-crotonic acid such as CH(Me)=CH--COO--,
CH(Me)=CH--COO--[A.sup.3O].sub.m--. A.sup.3 and m, including the
preferred ranges, are defined as stated above.
[0063] Examples of monoethylenically unsaturated structural units E
from the area of the dicarboxylic acid derivatives are monoesters
of maleic acid (HOOCH.dbd.CH(COO)--), the corresponding esters of
fumaric acid and of itaconic acid
(CH.sub.2.dbd.C--C(COOH)(CH.sub.2--COO).
[0064] Examples of structural units E which comprise carboxamide
structural units include (meth)acrylamides such as
CH.sub.2.dbd.CH--CO--N(R)--, CH.sub.2.dbd.CMe-CON(R)-- and maleic
monoamide (HOOCH.dbd.CH--CO--N(R))--, where R in each case
independently of one another is selected from H, C.sub.1-C.sub.30
alkyl, C.sub.6-C.sub.30 aryl and/or C.sub.7-C.sub.30 aralkyl, R
preferably being H or C.sub.1-C.sub.4 alkyl; more particularly
preferred from C.sub.1-C.sub.4 alkyl is methyl.
[0065] Preference is given to the method of utilizing copolymers
characterized in that the structural unit E in each case
independently is selected from a vinyl ether, allyl ether,
isoprenyl ether, (meth)acrylic ester, (meth)acrylamide, maleic
monoester and/or maleic monoamide unit. Especially preferred are
vinyl ether, (meth)acrylic ester and/or (meth)acrylamide units.
[0066] Preference is given to the method of utilizing characterized
in that the copolymer comprises as additional comonomer in
copolymerized form an unbranched polyether macromonomer of the
general formula E-L, where E and L have the meanings given above.
In the unbranched polyether macromonomer E-L, L is preferably a
linear structural unit of the formula -[A.sup.1O].sub.l-A.sup.2,
where A.sup.1 in each case independently is selected from
C.sub.2-C.sub.10 alkylene, C.sub.6-C.sub.10 arylene and/or
C.sub.7-C.sub.10 aralkylene, preferably --C.sub.2H.sub.4--, A.sup.2
in each case independently is selected from C.sub.1-C.sub.30 alkyl,
C.sub.3-C.sub.10 cycloalkyl, C.sub.6-C.sub.30 aryl and/or
C.sub.7-C.sub.30 aralkyl, preferably C.sub.1-C.sub.4 alkyl, and l
in each case independently is an integer from 7 to 30, preferably
from 12 to 25, especially preferably from 15 to 20.
[0067] The preferred range for the side chain length, defined via
the parameter l, has the advantage that the moderately long side
chains (preferably from 7 to 30) are able to make a contribution to
the dispersibility, while still not increasing the application
viscosity, more particularly the viscosity in the concrete, as a
result of excessive length.
[0068] Preference is given to the method of utilizing copolymers,
characterized in that the ethylenically unsaturated structural unit
E is present in the form of E*-S, where E* in each case
independently is selected from a vinyl ether, allyl ether,
(meth)acrylic ester and/or maleic monoester unit and S is a
(poly)alkylene glycol unit -[A.sup.3O].sub.m--, where A.sup.3 in
each case independently is selected from C.sub.2-C.sub.10 alkylene,
C.sub.6-C.sub.10 arylene and/or C.sub.7-C.sub.10 aralkylene,
A.sup.3 preferably being --C.sub.2H.sub.4--, and m is in each case
independently an integer from 1 to 50, preferably from 1 to 40,
especially preferably from 1 to 25. It is particularly preferred
for A.sup.3 in each case independently of one another to be present
to an extent of more than 60 mol %, based on all of the structural
units of the formula -[A.sup.3O].sub.m--, in the form of
--C.sub.2H.sub.4--.
[0069] If E is present in the form of E*-S, there is preferably at
least one alkylene oxide unit present as a "spacer" (abbreviated S)
between E* and the relatively sterically bulky, branched structural
unit V.sub.kL.sub.k+1. This leads to a higher reactivity in the
synthesis of the polyether macromonomer (B) (etherification or
esterification, as will be shown below), and increases the yield of
(B). In the case of amines, the reactivity with respect to
(meth)acrylic acid, (meth)acrylic anhydride, (meth)acryloyl
chloride or maleic anhydride is higher in any case, since
carboxamides are formed. Accordingly, a spacer does not bring such
great reactivity advantages.
[0070] In the general formula (I), V is a branched structural unit
--CH(CH.sub.2O--).sub.2. V is a relatively hydrophilic polyether
structural unit and therefore contributes to the water solubility
of (B). For illustration it will be mentioned again that the actual
branching site is the tertiary carbon atom, which is substituted by
one H atom and two (CH.sub.2O--). The polyether macromonomer (B)
undergoes branching, in line with the general formula (I)
E-V.sub.kL.sub.k+1, starting from the unsaturated structural unit E
by way of the branched structural unit V.sub.k. The index k here
indicates the number of structural units V and hence of branching
sites. In the hypotheoretical comparative case (not in accordance
with the claims) of k being 0 there would be a single, unbranched
side chain of the prior art (E-L). In the case where k is 1, two
polyether side chains are introduced; in the case where k is 2
three polyether side chains are introduced; and so on.
[0071] V in the synthesis of the polyether macromonomer (B)
originates from glycerol derivatives, more preferably from
epichlorohydrin, whose reactivity is the greatest among the
glycerol derivatives.
[0072] L is a linear structural unit of the formula
-[A.sup.1O].sub.l-A.sup.2, the parameters A.sup.1, A.sup.2 and l
meeting the definition stated above. The index l denotes the number
of repeating alkylene oxide units and, like A.sup.1 and A.sup.2,
may be the same or different independently of one another in a
polyether macromonomer (B); that is, l may adopt different values
within the same polyether macromonomer, and A.sup.1 and A.sup.2 may
be the same or different.
[0073] L comprises linear, unbranched (poly)(cyclo)alkyl,
(poly)aryl and/or (poly)aralkyl structural units, preferably
(poly)alkylene structural units. The structural units L cap the
polyether macromonomer. The number of branching structural units V
and L is linked via the parameter k. The simple rule here is that
the number of linear structural units L is greater by 1 and the
number of branching structural units V. L represents a hydrophilic
and readily water-soluble structural unit if A.sup.1 is
C.sub.2H.sub.4--. For this reason, A.sup.1 is preferably
C.sub.2H.sub.4--.
[0074] In the synthesis of the polyether macromonomer (B), L
originates from monoalcohols of the formula
HO-[A.sup.1O]-A.sup.2.
Synthesis of the Polyether Macromonomers (B)
[0075] The polyether macromonomers (B) may be synthesized in an at
least two-stage operation. A distinction is made between the
process stage (I) of reacting a linear monoalcohol to form a
branched monoalcohol, and the process stage (II) which comprises
the reaction of the resulting branched monoalcohol to give the
ethylenically unsaturated polyether macromonomer (B)
(etherification or esterification with suitable ethylenically
unsaturated reagents).
[0076] In certain intermediate stages, the branched monoalcohol may
also be transformed, optionally, into an amine, in which case
subsequently, in the process stage (II), during the reaction with
suitable ethylenically unsaturated carboxylic acids or carboxylic
acid derivatives, carboxamides are formed.
[0077] Likewise optionally, the branched monoalcohol of the general
structural formula (II) may be alkoxylated, thus giving a polyether
monoalcohol of the formula HO-[A.sup.3O].sub.m-V.sub.kL.sub.k+1,
with a so-called spacer. In the (B) polyether macromonomer, E is
then present in the form of E*-S. All of the parameters E*,
A.sup.3, m, V, k and L have the definitions stated above.
Process Stage (I)
[0078] Process stage (I) constitutes the reaction of a linear
monoalcohol of the formula HO-[A.sup.1O].sub.l-A.sup.2 with a
glycerol derivative, such as glycidol, glycerol carbonate or
epichlorohydrin, preferably epichlorohydrin. The product is a
branched polyether monoalcohol of the general formula (II)
HO-V.sub.kL.sub.k+1, (II)
where the parameters V, k, L, A.sup.1, l and A.sup.2 are defined as
stated above. It is possible to use the same or different alcohols
of the formula HO-[A.sup.1O].sub.l-A.sup.2.
[0079] Said reaction takes place at best in the presence of bases,
especially if epichlorohydrin is being used. The reactions can be
carried out in the presence of a catalyst. Examples of suitable
catalysts include organic and inorganic bases. Where epichlorhydrin
is used as the reactive glycerol derivative, the base serves not
only as a catalyst but also to neutralize the resultant
hydrochloric acid. Examples of suitable inorganic bases include
alkali metal carbonates and, in particular alkali metal hydroxides
such as NaOH and KOH. Examples of suitable organic bases include
tertiary amines, more particularly triethylamine and
[2.2.2]diazabicyclooctane (DABCO), and also pyridine and
para-N,N-dimethylaminopyridine.
[0080] In one embodiment, the reaction of glycerol derivatives,
such as glycidol or glycerol carbonate, preferably epichlorohydrin,
can be carried out in a solvent. Examples of suitable solvents
include ethers, especially 1,4-dioxane, diisopropyl ether,
tetrahydrofuran ("THF") and di-n-butyl ether. Other suitable
solvents are n-butylacetate ("butyl acetate"), DMSO,
N,N-dimethylformamide ("DMF") and N-methylpyrrolidone, and aromatic
solvents such as toluene, for example.
[0081] In embodiments in which water is eliminated during the
reaction of the linear monoalcohol of the formula
HO-[A.sup.1O].sub.l-A.sup.2 with a glycerol derivative (e.g.
glycerol), it is possible to employ a water-removing agent, as for
example a molecular sieve, sodium sulphate or magnesium sulphate,
or the water formed may be removed by azeotropic distillation.
[0082] These reactions are described in detail in US2011/0015361
A1. Through targeted control of the temperature and of the
quantities of monomer, it is possible to obtain different branched
polyether macromonomers, typically in the form of mixtures. Since
the reactivity goes down as the number of k (chain length) goes up,
it is advantageous to raise the temperature in steps. At relatively
low reaction temperatures it is particularly advantageous to react
only part of the epichlorohydrin with the monoalcohol of the
formula (II), then to add further epichlorohydrin and to continue
the reaction at elevated temperature. This sequence, described in
US2011/0015361 A1, of substeps (adding epichlorohydrin, raising the
temperature, and chemically reacting) can be repeated a number of
times.
[0083] Generally speaking, these reactions furnish mixtures of
monoalcohols of the general formula (II), with different values of
k, but also with different kinds of constitutions for the same k.
Set out below are a number of examples of possible structures.
[0084] For the simplest case of k as 1, for example, the following
singly branched monoalcohol (IIa) is obtained from the reaction of
two equivalents of linear monoalcohol of the formula
HO-[A.sup.1O],-A.sup.2 with one equivalent of epichlorohydrin:
HO--CH[CH.sub.2O--[A.sup.1O].sub.l-A.sup.1].sub.2. (IIa)
[0085] One equivalent of (IIa) may undergo further reaction with
one equivalent of epichlorohydrin and one equivalent of
monoalcohols of formula HO-[A.sup.1O].sub.l-A.sup.2 to react, for
example, the following asymmetric product (IIb) (k=2):
##STR00005##
[0086] Two equivalents of (IIa) may undergo further reaction, for
example, with one equivalent of epichlorohydrin to give the
following symmetrical monoalcohol (IIc) (k=3):
##STR00006##
[0087] The structures (IIb) and (IIc) are constitutional
isomers.
[0088] One equivalent of (IIb) may undergo further reaction, for
example, with one equivalent of epichlorohydrin and one equivalent
of monoalcohol of the formula HO-[A.sup.1O].sub.l-A.sup.2 to give
the following asymmetric monoalcohol (IId) (k=3):
##STR00007##
[0089] One equivalent of (IIc) may undergo further reaction, for
example, with one equivalent of epichlorohydrin and one equivalent
of monoalcohol of the formula HO-[A.sup.1O]-A.sup.2 to give the
following asymmetric monoalcohol (IIe) (k=4):
##STR00008##
[0090] Preferred as polyether macromonomer (B) is a structural unit
E-V.sub.k+1 characterized in that V.sub.kL.sub.k+1 conforms to one
of the formulae (IIa), (IIb), (IIc) and/or (IId), with the proviso
that in the formulae (IIa), (IIb), (IIc) and (IId) in each case the
OH group is replaced by a single bond. E, V and L here have the
meanings stated above, and k is an integer from 1 to 3.
[0091] Optional conversion of the branched monoalcohols (II) to
monoamines As mentioned above, the branched monoalcohol of the
general formula (II) HO-V.sub.k+1 may also be transformed by a
number of intermediate stages into a branched monoamine of the
formula NH(R)-V.sub.kL.sub.k+1 (replacement of the OH group by an
amino group NH(R)). For this purpose first of all in general there
is an oxidation on the secondary alcohol function to give a ketone.
This is followed by amination with an amine NH.sub.2R, with
elimination of water, to give the corresponding imine. The
reduction of the imine with the hydrogen, for example, in the
presence of catalysts (e.g. nickel or the like) leads to the
corresponding branched monoamine. The monoamines have the
structural formula NH(R)-V.sub.kL.sub.k+1, where R has the meanings
stated above.
Process Stage (II)
[0092] In the second process stage (II) the branched monoalcohol II
(e.g. the structures IIa, IIb, IIc, IId, IIe) may be modified by
the introduction of an ethylenically unsaturated structural unit
(E) to give the polyether macromonomer (B), as for example through
the reaction with acetylene to give a vinyl ether. The reaction
with (meth)allyl halides, preferably (meth)allyl chloride, leads
for example to corresponding (meth)allyl ethers. With (meth)acrylic
acid, (meth)acrylic anhydride or (meth)acryloyl halides, the
corresponding (meth)acrylic esters are obtained. The ethylenically
unsaturated structural unit may also be introduced by reaction with
maleic anhydride, in which case the corresponding maleic monoester
is obtained.
[0093] In an analogous way, from the branched monoamines
NH(R)-V.sub.kL.sub.k+1, through reaction with (meth)acrylic acid,
(meth)acrylic anhydride or (meth)acryloyl halides, the
corresponding carboxamides are obtained, or, in the case of maleic
anhydride, the maleic monoamide.
[0094] The respective esterification, amidation and etherification
reactions are well known in the prior art and are preferably
carried out under dehydrating conditions.
[0095] For the reaction with acetylene, it is possible to employ
one or more catalysts, preferably selected from basic catalysts.
Particularly suitable is KOH.
[0096] The reaction with acetylene can be carried out with or
without solvent. Examples of suitable solvents include
N-methylpyrrolidone, N-ethylpyrrolidone, toluene, xylene, THF and
dioxane. The reaction with acetylene can be carried out, for
example, at temperatures in the range from 80 to 160.degree. C.,
preferred temperatures being around 120.degree. C., as for example
110 to 130.degree. C. The acetylation can be carried out under
atmospheric pressure or, preferably at elevated pressure, as for
example at 2 to 30 bar.
[0097] The method of utilizing may be characterized in that A.sup.1
in each case independently is present to an extent of more than 60
mol %, more preferably to an extent of more than 80 mol %, based on
all of the structural units of the formula -[A.sup.1O].sub.l, in
the form of --C.sub.2H.sub.4--, A.sup.2 in each case independently
is selected from C.sub.1-C.sub.4 alkyl, k is an integer from 1 to 3
and l in each case independently is an integer from 2 to 100.
[0098] The polyether macromonomers (B) thus selected have the
advantage that on account of the polyalkylene oxide component they
are highly water-soluble and exhibit a good dispersing effect.
[0099] The method of utilizing may be characterized in that the
branched polyether macromonomer (B) has a molecular weight in the
range from 700 to 15 000 g/mol, preferably from 1500 to 10 000
g/mol and more preferably from 3000 to 8000 g/mol. An advantage is
that an acceptable dispersing effect and low viscosities in the
application can be obtained.
[0100] The method of utilizing may be characterized in that the
molar ratio of (A) acid monomer to (B) polyether macromonomer is
from 20/1 to 1/1, preferably 15/1 to 1.5/1 and more preferably from
10/1 to 3/1. Especially in the case of relatively high molecular
weights of the polyether macromonomer (B), relatively high
fractions of acid monomers (A) are advantageously, in order to
compensate the high mass of polyether macromonomer (B) by the
presence of a greater number of anionic so-called anchor groups,
which are able to interact with the cement surface, more
particularly with calcium ions. Particular preference is given to a
polyether macromonomer (B) molecular weight in the range from 3000
to 8000 g/mol and a molar ratio of (A) acid monomer to (B)
polyether macromonomer of 13/1 to 3/1, especially preferably of
10/1 to 5/1.
[0101] The method of utilizing may be characterized in that the
copolymer is obtainable by radical polymerization in the presence
of the ethylenically unsaturated acid monomer (A) and of the
ethylenically unsaturated polyether macromonomer (B), so that in
total at least 45 mol %, preferably at least 80 mol %, of all of
the structural units of the copolymer have been produced by
copolymerization of acid monomer (A) and polyether macromonomer
(B).
[0102] It is also possible for further ethylenically unsaturated
monomers (C) to be copolymerized as well. Suitable comonomers are
ethylenically unsaturated compounds which can be copolymerized
radically with the comonomers (A) and (B). Examples include the
following: C.sub.1-C.sub.10 alkyl esters of ethylenically
unsaturated monocarboxylic or dicarboxylic acids, more particularly
of (meth)acrylic acid, vinyl acetate, vinylaromatics such as, in
particular, styrene and .alpha.-methylstyrene, .alpha.-olefins such
as, in particular C.sub.12-C.sub.20 .alpha.-olefins, additionally
vinyl chloride, acryloylnitrile and N-vinylpyrrolidone. Preferred
examples of C.sub.1-C.sub.10 alkyl esters of ethylenically
unsaturated monocarboxylic acids are methyl (meth)acrylate, ethyl
(meth)acrylate, n-butyl (meth)acrylate and 2-ethyl hexyl
(meth)acrylate. Preferred in particular are C.sub.1-C.sub.10 alkyl
esters of ethylenically unsaturated monocarboxylic or dicarboxylic
acids, more particularly of acrylic acid.
[0103] Also provided are dispersants for inorganic binders,
comprising a copolymer as defined above. Besides the subject
copolymers, the subject dispersant may also comprise other
formulating ingredients such as rheological assistants (e.g.
cellulose ethers or starch ethers) and/or redispersible polymer
powders, defoamers, air entrainers and so on. It is also possible
to use other polycarboxylate ethers in formulations, or other
superplasticizers such as lignosulphonates or melamine
sulphonates.
[0104] Also provided are building material mixtures comprising
inorganic binders, preferably cement, and a dispersant for
inorganic binders, comprising a subject copolymer described
above.
[0105] The inorganic binder or the inorganic binders here is or are
preferably selected from cements, more particularly portland
cements and aluminate cements, from .alpha.-calcium sulphate
hemihydrate, .beta.-calcium sulphate hemihydrate, anhydrite and
lime, from slags, more particularly blast furnace slag, slag sand,
ground slag sand, electrothermal phosphorous slag and stainless
steel slag, from pozzolanic binders, more particularly fly ashes,
preferably brown coal fly ash and mineral coal fly ash,
microsilica, metakaolin, natural pozzolans, more particularly tuff,
trass and volcanic ash, natural and synthetic zeolites, calcined
oil shale, and mixtures of these.
[0106] It is possible to dry the subject dispersants by
conventional drying methods such as spray drying, for example, and
to incorporate the resultant, largely water-free products into
inorganic binders. The dry mortars obtained in this way can be used
on the construction site itself by being batch-mixed with water
(without addition of superplasticizers). The amount of the subject
dispersant that is added is typically in the range of from 0.1 to 1
wt %, based on the inorganic binder or binders, preferably 0.2 to
0.6 wt %. The dry mortars often include rheological assistants such
as cellulose ethers and/or redispersible polymer powders,
defoamers, air entrainers and so on.
EXAMPLES
1. General Experimental Procedure for Preparing Branched Polyether
Monoalcohols of The General Structural Formula (II)
(HO-V.sub.kL.sub.k+1)
[0107] A 2-litre flask with dropping funnel, magnetic stirrer and
reflux condenser was charged with a solution of the corresponding
methylpolyethylene glycol (see Table 1) in 1177 ml of dioxane. With
stirring, 40 g of KOH pellets are added. This initial charge is
heated to 105.degree. C. and the required amount of epichlorhydrin
(corresponding to Table 1), in solution in dioxane, is added over a
period of customarily 30 minutes. The reaction solution is
subsequently stirred at 105.degree. C. for 17 hours and then cooled
to room temperature. The potassium chloride formed is removed by
filtration, and the solvent is removed under reduced pressure at 35
mbar. Ten different types of branched polyether monoalcohols of the
general structural formula (II) (HO-V.sub.kL.sub.k+1) were
obtained, and they were either reacted directly to give polyether
macromonomers (B) of the general structural formula (I)
(E-V.sub.kL.sub.k+1) or, as in the case of sample 10, were
alkoxylated with 10 equivalents of ethylene oxide (spacer), or, as
in the case of sample 4, were transformed into an amine derivative
(general formula NH(R)-V.sub.kL.sub.k+1) with replacement of the
hydroxyl group by an NH.sub.2 group.
[0108] In this case the amination was carried out as follows
(amination for macromonomer 4): To carry out the amination, 1 mol
of the branched monoalcohol and a catalyst (25 g) were placed into
an autoclave vessel. The catalyst contains Ni, Co, Cu,
Al.sub.2O.sub.3 and Sn on graphite (US 2011/0137030).
[0109] The autoclave was flushed with nitrogen in order to prevent
oxidation of catalyst. 42.6 g of ammonia were likewise placed into
the autoclave, and the desired hydrogen partial pressure of 40 bar
at room temperature was set. The reaction was initiated by heating,
and the start of the reaction was specified as the attainment of a
temperature of 214.degree. C. Thereafter the reaction product was
allowed to stand with stirring at 210.degree. C. for a further 10
hours. The discharge from the experiment was freed from traces of
the catalyst by means of a pressure filtration. This gave 28 g of
the branched amine 4.
[0110] Reaction with ethylene oxide (spacer-modified alcohol for
macromonomer 10): The branched monoalcohol (1 eq.) and potassium
methoxide (1 eq.) are weighed out and agitated on a rotary
evaporator at a pressure of about 20 mbar for 120 minutes at
90.degree. C., and the methanol formed in this reaction is taken
off.
[0111] This reaction solution is transferred to the reactor, which
has been dried beforehand, and the reactor is closed and inertized
with nitrogen to 5 bar three times. The batch is subsequently
heated to 120.degree. C. with stirring and a preliminary nitrogen
pressure of 3.5 bar is set. Then 0.1 equivalent of ethylene oxide
is metered in under mass control over the course of 20 minutes.
Following onset of the reaction, a further 9.9 equivalents of
ethylene oxide are metered in under mass control over the course of
420 minutes. After the end of metering, the batch is stirred at
120.degree. C. for a further 420 minutes. The batch is cooled to
80.degree. C. and flushing takes place with nitrogen (about 0.5
m.sup.3/h) into the off-gas line for 30 minutes, and the clear,
yellowish product is drained from the reactor. The yield is
quantitative.
2. General Experimental Procedure for the Preparation of Polyether
Macromonomers (B) of the General Structural Formula (I)
(E-V.sub.k+1)
[0112] 2.1 Vinylation to the Vinyl Alcohol by Reaction of the
Branched Polyether Monoalcohols with Acetylene A 2.51 autoclave was
charged with 1 mol of the branched polyether monoalcohol and 10 g
of KOH, and this initial charge was inertized with nitrogen (2 bar)
and thereafter heated to 120.degree. C. Acetylene was then injected
with a pressure of 20 bar and the reaction mixture was stirred at
120.degree. C. and 20 bar until a total of 26 g of acetylene had
been taken up. Thereafter it was cooled to room temperature and let
down and the residue, after heating at 60.degree. C. for 3 hours
with stirring, was degassed and then removed from the autoclave.
The conversion is quantitative. A comparison may be made in
particular with sample 5 from Table 1. 2.2 Reaction with
Methacryloyl Chloride to the Methacrylic Ester:
[0113] 0.01 mol of the respective branched macroalcohol from Table
1 (product of the respective methylpolyethylene glycol and
epichlorohydrin) is melted in a round-bottomed flask at 80.degree.
C. Slowly, 0.04 mol of triethylamine and 600 ppm of p-methoxyphenol
are added. Then 0.03 mol of triethylamine is added dropwise and the
mixture is stirred at 80.degree. C. for 6 hours.
[0114] After cooling, the solid material is dissolved in 50 ml of
THF and the precipitate is isolated by filtration. Then 30 ml of
0.1 N HCl solution are added and the aqueous phase is removed.
[0115] The organic phase is freed from the solvent. This gives the
macromonomer with a selectivity of 97% (determined by HPLC and
NMR).
2.3 Reaction with Methylacrylic Anhydride to the Methacrylic
Ester:
[0116] 0.1 mol of the respective branched alcohol from Table 1
(product of the respective methylpolyethylene glycol and
epichlorohydrin) is melted at 90.degree. C. in a flask. Following
addition of 0.1 mol of Na.sub.2CO.sub.3 and 0.0013 mol of butylated
hydroxytoluene, 0.27 mol of methacrylic anhydride is added
dropwise. The mixture is stirred for 4 hours. Then 300 ml of water
are added and stirring takes place at 60.degree. C. for 1 hour. The
solution is adjusted with H.sub.3PO.sub.3 to a pH of 6. Excessive
methacrylic acid is extracted by shaking with water or removed by
filtration over basic aluminium oxide. This gives the desired
macromonomer in selectivities of more than 96% (HPLC and NMR).
TABLE-US-00001 TABLE 1 Data of the polyether macromonomers (B)
Polyether macromonomer (B) (No.) 1a 1b 2 3 6 7 8 9 10 .sup.1) 4
.sup.2) 5 Side chain length 750 750 2000 750 2000 350 350 350 750
750 350 (g/mol) of the g/mol g/mol g/mol g/mol g/mol g/mol g/mol
g/mol g/mol g/mol g/mol methyl-polyethylene [0.667 [0.667 [0.667
[0.455 [0.247] [1.429 [0.455 [1.429 [0.667 [0.667 [1.429 glycols
used (.dbd.HO-L) mol] mol] mol] mol] + mol] mol] + mol] mol] mol]
mol] and amount in mol 2000 705 g/mol g/mol [0.455 [0.455 mol] mol]
Epichlorohydrin 0.583 0.583 0.583 0.796 0.216 1.072 0.796 1.250
0.583 0.583 1.250 mol mol mol mol mol mol mol mol mol mol Molecular
weight 1844 1844 4057 4481 6550 1611 1636 1612 2284 1844 1864
(determined by GPC) g/mol g/mol g/mol g/mol g/mol g/mol g/mol g/mol
g/mol g/mol Polymerizable Methacrylic ester Methacryl- Vinyl ether
group E amide .sup.1) After the reaction of the methylpolyethylene
glycol with epichlorohydrin, the branched monoalcohol was
alkoxylated with 10 equivalents of ethylene oxide. .sup.2) After
the reaction of the methylpolyethylene glycol with epichlorohydrin,
the branched monoalcohol was hydroaminated. 1a and 2-10: ester
prepared from methacrylic anhydride 1b: ester prepared from
methacryloyl chloride
Polymerization of the Polyether Macromonomers (B) with Methacrylic
Acid (Acid Monomer A):
[0117] A Buchi double-wall glass reactor is charged with 47 g of
water and this initial charge is heated to 60.degree. C. with
nitrogen blanketing. Over a period of 4 hours, a solution of 0.01
mol of the corresponding macromonomer and the corresponding amount
of methacrylic acid is then added dropwise (Table 2). The initiator
(sodium persulphate) is metered in over the course of 4.5 hours as
a 7% aqueous solution with 3 mol %, based on the amount of
polymerizable double bonds (amount of macromonomer+amount of
methacrylic acid). Following after polymerization for an hour, the
polymer solution is cooled and neutralized to a pH of 6.5 with
aqueous sodium hydroxide solution. The polymer solution is diluted
to give a solids content of 30%.
Polymerization of the Polyether Macromonomers (B) with Acrylic Acid
(Acid Monomer A):
[0118] A glass reactor equipped with stirrer, pH electrode and a
number of feed facilities is charged with 40 g of deionized water
and 0.1 mol of the corresponding macromonomer and this initial
charge is brought to a polymerization start temperature of
15.degree. C. Subsequently, in a separate feed vessel, the required
amount of acrylic acid (see Table 1) is mixed with 16 g of water
(solution A). In parallel with this, a 6% strength solution of
Bruggolit.RTM. E 01 is prepared (solution B). With stirring and
cooling, first 0.24 g of 3-mercaptopropionoic acid, 0.012 g of
Fe.sub.2(SO.sub.4).sub.3 and 0.64 g of a 30% strength aqueous
H.sub.2O.sub.2 solution are added. At the same time as this, the
addition of solutions A and B is commenced. Solution A is added
with a metering rate of 24 ml/h, solution B is added at a rate of
15.2 ml/h until the solution is peroxide-free. The polymer solution
obtained is then adjusted to a pH of 6.5 with 50% strength aqueous
sodium hydroxide solution. The polymer solution is diluted with
water until it has a solids content of 30%. The results of the
copolymerizations are summarized in Table 2.
TABLE-US-00002 TABLE 2 Copolymers of (A) and (B) Macro- (B)
(mol)/(A) monomer (mol) M.sub.w Copolymer (B) (type* of (A))
[g/mol] 1 1a 1/5 (MAS) 21 000 2 2 1/7 (MAS) 27 000 3 3 1/7 (MAS) 25
000 5 5 1/8 (AS) 33 000 6 6 1/7 (MAS) 25 000 7 7 1/5 (MAS) 29 000 8
8 1/5 (MAS) 18 000 9 9 1/5 (MAS) 18 000 10 10 1/5 (MAS) 18 000 11
1a 1/1/5 21 000 (HEMA/MAS) 12 1b 1/12 (MAS) 23 000 13 1b 1/20 (MAS)
17 000 14 1b 1/12 (MAS) 20 000 15 1b 1/12 (MAS) 45 000 16 1b 1/12
(MAS) 24 000 *Abbreviations for type of acid monomer (A): AS:
Acrylic acid MAS: Methacrylic acid HEMA: Hydroxyethyl
methacrylate
Mortar Tests
[0119] The mortar tests were carried out in accordance with the DIN
EN 1015-3 standard. The cement used here was a Karlstadt cement
from Schwenk. In the experiments, a sand/cement ratio of 2.2 was
used. In this case a mixture of 70% standard sand (Normensand GmbH,
Beckum) and 30% quartz sand was used. The water/cement ratio was
set always at 0.43. The addition of the superplasticizer is
indicated in wt % of solid, based on the cement.
TABLE-US-00003 TABLE 3 Mortar results with Karlstadt cement Level
of Slump spread [cm] Copolymer addition 0 min 10 min 30 min Glenium
.RTM. 0.17 24.2 25.9 25.6 ACE 440* 1 0.23 23.4 21.6 19 2 0.18 23.5
23.3 21.7 3 0.22 24.5 23.1 21.3 5 0.21 23.7 22.1 19.2 6 0.18 23.5
23.3 21.7 7 0.4 23.8 24.2 21.8 8 0.21 23.6 25.2 25 9 0.32 23.9 24.1
22.7 10 0.33 23.8 23.3 23.2 11 0.33 23.7 24.1 23.8 12 0.25 25 23.3
20.4 13 0.3 24.5 24.8 23.8 14 0.3 24 25.2 23.9 15 0.32 24.4 24.1
22.7 16 0.25 25 23.3 20.4 *Glenium ACE 440 is, for comparison, a
polycarboxylate ether with the monomers acrylic acid, maleic acid
and ethoxylated hydroxybutyl vinyl ether (linear side chain). It is
available from BASF Construction Chemicals Italia Spa.
[0120] The level of addition of the superplasticizer in Table 3 is
indicated in wt % of solid, based on the cement.
[0121] On the basis of these results it is clear that the amount of
water required to plasticize a mortar to a particular slump spread
is drastically reduced by the addition of these polymers. If the
superplasticizer is not added, a water/cement ratio (w/c) of 0.55
is needed in order to obtain a slump spread of 23-25 cm.
[0122] The superplasticizers with side chain branching, as compared
with linear side chains (comparative experiment with Glenium.RTM.
ACE 440), require a higher acrylic acid fraction in order to
achieve a similar plasticization.
[0123] Further mortar tests with Monselice cement were carried out
with a cone as described in DIN EN 1015-3. The results are the
flows indicated in Table 4.
[0124] The materials and mortar formula used were as follows:
cement: Monselice CEM 152.5 R w/c=0.42-0.44 s/c=3 (standard sand
(Normensand GmbH, Beckum))
[0125] All of the polymers were used as 20% strength solutions,
formulated with defoamer (4 wt % tributyl phosphate, based on the
solids of the copolymer).
TABLE-US-00004 TABLE 4 Mortar results with Monselice cement % by
wt. of solid Copolymer copolymer based on Flow [cm] No. w/c cement
0 min 30 min Glenium .RTM. 0.44 0.24 131 131 ACE 440* 6 0.44 0.60
133 100 2 0.44 0.32 129 97 1 0.44 0.32 127 95 Glenium .RTM. 0.42
0.24 110 112 ACE 440* 7 0.42 0.60 114 100 8 0.42 0.36 112 105 10
0.42 0.44 110 103 9 0.42 0.40 108 93 *Glenium .RTM. ACE 440 is a
polycarboxylate ether with the monomers acrylic acid, maleic acid
and ethoxylated hydroxybutyl vinyl ether. It is available from BASF
Construction Chemicals Italia Spa.
[0126] Concrete tests, including measurement of the plastic
viscosity
[0127] The cement used for the viscosity measurements was CEM 152.5
from Montselice and another CEM I 52.5 cement. The following
mixture design was used:
TABLE-US-00005 Sand 0-4 1050 kg/m.sup.3 Gravel 8-12 770 kg/m.sup.3
Cement type I 52.5 400 kg/m.sup.3 Water 180 kg/m.sup.3
[0128] The ambient temperature was 20.degree. C. and the
superplasticizers were used in the form of 20% strength solutions,
formulated with 4 wt % of defoamer (tributyl phosphate) based on
the solids of the superplasticizer.
[0129] In order to obtain comparable results, the amount of
additive was calculated such that all of the fresh concretes gave a
slump of 22 to 24 cm after 5 minutes in accordance with DIN EN
12350. The water/cement ratios were set at 0.45 and the measurement
was carried out after 5 minutes and after 20 minutes. The results
are summarized in Tables 5a (Monselice cement) and 5b.
[0130] Apart from the plasticization, another significant factor
for the use as stipulated is the viscosity of the fresh concrete.
The viscosity is a measure of the pumpability and processing
properties of the fresh concrete. Lower values for the viscosity
result in better processing properties and hence in better
pumpability (Gleitrohr-Rheometer: Ein Verfahren zur Bestimmung der
Flie.beta.eigenschaften von Dickstoffen in Rohrleitungen [Sliding
pump rheometer: A method to establish the flow properties of
viscous media in pipelines], Thesis by Dr Knut Jens Kasten, TU
Dresden. Shaker Verlag; 1.sup.st edn. (July 2010)).
[0131] The plastic viscosities of the fresh concrete were measured
in an IKAR rheometer (reference: E. P. Koehler, D. W. Fowler
(2007). "ICAR Mixture Proportioning Procedure for SCC"
International Center for Aggregates Research, Austin, Tex.).
TABLE-US-00006 TABLE 5a Slump flow and plastic viscosities with
Montselice CEM I 52.5 R % by wt. solids copolymer Slump (cm)
Plastic based on Air pore Slump flow (cm) viscosity Copolymer
cement content (%) 5 Min 20 Min .mu. (Pa * s) Glenium .RTM. 0.24
1.9 23 23 184 ACE 440* 43 -- 1 0.35 -- 24 23.5 151 52 50 2 0.3 1.9
22 21 152 38 35 6 0.42 1.8 23 23.5 147 54 47 10 0.46 2.3 21 16 128
-- -- 8 0.36 2.0 23.5 23.5 140 46 46 9 0.4 2.1 24 24 136 50 47
*Glenium .RTM.ACE 440 is a polycarboxylate ether with the monomers
acrylic acid, maleic acid and ethoxylated hydroxybutyl vinyl ether.
It is available from BASF Construction Chemicals Italia Spa.
TABLE-US-00007 TABLE 5b Slump flow and plastic viscosities with CEM
I 52.5 R % by wt. solids copolymer Slump (cm) Plastic based on Air
pore Slump flow (cm) viscosity Copolymer cement content (%) 5 Min
20 Min .mu. (Pa * s) Glenium .RTM. 0.18 2.1 23.5 19 273 ACE 440* 46
30 1 0.33 2.4 23 14 170 37 -- 2 0.21 2.8 23.5 12 187 43 --
[0132] Commercial superplasticizers are often comb polymers with
linear polyethylene glycol side chains (PEG side chains). However,
when used as water reducers, these superplasticizers lead to
relatively high plastic viscosities on the part of the fresh
concrete. This makes it more difficult to pump the fresh concrete
and to place it into moulds.
[0133] The subject dispersants plasticize concretes and make it
possible in particular to obtain low concrete viscosities. As is
apparent from the comparison of Glenium.RTM. ACE 440 with the
subject copolymers, the subject copolymers represent a good
possibility for preparing fresh concretes having low viscosities
even in the case of relatively low w/c values. It is also noted
that the viscosity of the concrete without added superplasticizer
could not be properly measured, since, because of the lack of
plasticity, much higher w/c values would otherwise have to be used
here.
* * * * *